Hypothermia is generally defined as a body temperature above 37°C but below 38°C, and is not as pronounced as high fever chills. Patients with hypothermia may feel slightly warm or light-headed, and some patients may experience hot flashes and night sweats. Hypothermia is most commonly associated with infection by Mycobacterium tuberculosis, i.e., various types of tuberculosis, such as pulmonary tuberculosis. In addition to prolonged hypothermia, patients often have a cough, coughing sputum, blood in the sputum, hot flashes and night sweats, chest pain, and even weight loss. Hypothermia is also common in some chronic infectious diseases, such as chronic pyelonephritis or chronic urinary tract infections. Patients with hematological diseases, such as chronic leukemia, anemia, and chronic granulocytic leukemia can develop hypothermia. There are also non-infectious diseases such as hyperthyroidism, rheumatic fever, malignancy, hemolytic reactions, and allergic reactions that can also present with hypothermia. Many diseases can present with hypothermia along with other symptoms associated with it, so they should be treated for the infectious agent; if they are caused by non-infectious factors, a detailed examination should be performed to clarify the cause and treat the primary cause of the hypothermia. In conclusion, hypothermia of unknown origin should not be abused with antipyretic drugs.